It’s always disturbing to hear about intentional cases of food adulteration – the melamine in infant formula, for example, because it represents a concerted effort to deceive, and in many cases, harm the public. But how common is such nefarious manipulation of our food?

More common than you think, according to food science experts. They call it economic adulteration – which is the deliberate substitution or addition of compounds to a food to make it cheaper to make. Carbohydrate-heavy foods like fruit juices are the most popular target, according to the Grocery Manufacturers Association (GMA); anywhere from 5% to 25% of these foods are adulterated.

The manipulation can take many forms, from mislabeling to dilution to outright subbing in of cheaper ingredients (beet sugar is a common inexpensive sweetener, for instance) or introduction of unapproved agents like melamine.

A representative of Eurofins, a French lab that specializes in analyzing foods and detecting adulterants, reported that the most common form of adulteration – in 22% of fruit juice manipulations — is the addition of other sugars to boost the natural level of sweetness. That’s followed by the mixing in of other fruits at 15% (cheaper grape juice is often used to “fill out” more expensive pomegranate juice) and the addition of other flavors at 16%. Pomegranate juice is the most commonly adulterated fruit beverage, with 50% of tested samples showing some form of adulteration.

The GMA says that exotic fruit drinks are the next likely target for such fraudulent modifications, but the good news is that labs like Eurofins are raising the bar on detection methods. Using sophisticated nuclear magnetic resonance techqnies, they can tease apart the different chemical forms, or isotopes that various compounds can take and thus develop signatures of fruit juices that will make it easier for food scientists to pick up any deviations from these norms.

So far, the popular acai berry juices seem to have escaped major adulteration – it’s unique enough because it has a high fat content and an signature array of nutrients and vitamins that any changes to it would be easy to detect. But when the GMA recently asked 10 makers of acai berry juice to certify that their product was authentic, only one, ITI Tropicals, complied. Let’s hope that’s not a trend that continues.